Bear Mountain – Wearing "Open All Trails Now" stickers, a standing-room-only crowd of hikers trudged into the Bear Mountain Inn last night to force the removal of old artillery shells littering Storm King State Park.

Closed officially by exploding shells in a hot forest fire in 1999 that burned down to bedrock, the 1,900-acre park hugging the Hudson River offers spectacular views from peaks more than 1,000 feet high. Shells were fired at the ridges during Army training at West Point until the 1940s.

Last night, the U.S. Army Corps of Engineers promised to wrap up its recent probe for the shells so that the hikers can enjoy this fall's foliage season, at least on two-thirds of the park's trails that have been declared ordnance free.

But 453 acres with more than 700 "unexploded ordnance" will remain closed until the shells are blown up or carried away.

Environmental groups yesterday, including Scenic Hudson, backed the early shell removal and trail openings.

How long that will take was unclear last night. Hikers pushed to get into the shell-laden section as soon as possible, pointing out that the Corps' draft report has already said that the area has been cleared to 25 feet on each side of marked trails and could be trod by day hikers who stick to the path.

Fearing those who do not obey don't-stray signs, like a 76-year-old expert Queens hiker who was killed in May when he went off the trail on nearby Schunnemunk Mountain and was hit by a huge rock, the Corps is taking a conservative position, said shell removal project manager James T. Moore.

Laughter followed his admission that the only time the shells have gone off in all the years hikers have been visiting the mountain range was in the 1999 fire.

No one's ever been hurt, but it's fear of liability that's driving the Corps' caution, said Moore.

He said "people will relic hunt and put these [shells] by camp fires," or take them home for the mantel.

The hikers also urged the Corps to make room in its decision for hunters.

Still unknown last night was what do local firefighters do if there's another big fire in the mountains like 1999. The Corps' draft recommendation is don't fight the fires until there's a firefighting plan for the area still containing artillery rounds.

Cornwall fire Chief Pat Hines said earlier this week, "We've never been informed by anyone where the ordnance is. Right now I don't know if I would send personnel up there."

Moore said he's extended the public comment period on the Corps' risk analysis of what may be a $4 million to $7 million shell removal job until Aug. 31. Reach him at 212-264-0554. Copies of the draft recommendations are in the Cornwall and Highland Falls libraries.